1. Field of the Invention
The present invention relates generally to filtering devices and, more particularly, to an opposed axial flow filtering apparatus having a plurality of filtering elements arranged in pairs which allows for flow modulation over a wide range.
2. Description of the Prior Art
An axial flow filter is disclosed in U.S. Pat. No. 3,308,956 to Yee et al., and an improved version of this filter is described in British Patent No. 2,094,652 B. The oil filters described in these two patents are generally suitable for bypass filtering of circulating oil in an internal combustion engine, and provide for axial flow of the oil in one direction through a single annular filter element. Although suitable for their intended use, it is difficult to adapt these filters to accomodate a wide range of flow rates or to adjust the pressure drop across the filter, as would be desirable in a number of other fluid filtering applications.
It would therefore be desirable to provide an axial flow filter which can be adapted to handle widely varying flow rates, as well as having an adjustable pressure drop through the filter.